Mumbai: Ethanol blending involves mixing plant-based alcohol into petrol to reduce dependence on imported crude oil. While the programme has scaled rapidly, concerns are mounting over its environmental cost, particularly water consumption.
India’s ethanol production capacity has reached 1,822 crore litres, with a large share concentrated in water-stressed regions such as Delhi and Maharashtra. The primary feedstocks, sugarcane, maize, and increasingly rice, are among the most water-intensive crops cultivated in the country.
According to IPCC author Anjal Prakash, ethanol blending could aggravate water scarcity due to the heavy water footprint of these crops. “Most of the raw material, sugarcane and increasingly maize, is extremely water-intensive to grow and process,” he said.
Rice, in particular, has emerged as a key concern. The government allocated 52 lakh tonnes of rice for ethanol production in 2024–25 and has set a higher target of 90 lakh tonnes for 2025–26. To support this shift, authorities plan to reduce the share of broken rice distributed under the public distribution system from 25% to 10%, diverting the surplus to ethanol distilleries.
Data highlights the scale of the issue. Producing one litre of ethanol from rice requires approximately 10,790 litres of water, according to Food Secretary Sanjeev Chopra. This includes water used primarily during cultivation, with growing one kilogram of rice consuming between 3,000 to 5,000 litres. Since around 2.5 to 3 kilograms of rice are needed to produce one litre of ethanol, the total water footprint exceeds 10,000 litres.
In comparison, maize requires about 4,670 litres of water per litre of ethanol, while sugarcane needs around 3,630 litres, still substantial, but significantly lower than rice.
The inefficiency is further underscored by conversion ratios. One tonne of rice yields only about 470 litres of ethanol, making it one of the most water-intensive sources of fuel production.
Environmental concerns extend beyond water usage. Ethanol production generates large quantities of wastewater, known as vinasse, which can contaminate surface and groundwater if not properly treated, Prakash added.
The issue also highlights a perceived imbalance in accountability. Om Prakash, Editor of Kisan Tak, noted the contrast between agricultural and industrial water usage. “When a farmer grows 1 kg of rice using 3,000 to 5,000 litres of water, they are blamed for depleting resources. But industries use over 10,000 litres to produce one litre of ethanol, and are rarely held accountable,” he said.